171.
Predict the correct intermediate and product in the following reaction.
\[\begin{align}
& {{H}_{3}}C-C\equiv CH\xrightarrow[HgS{{O}_{4}}]{{{H}_{2}}O,{{H}_{2}}S{{O}_{4}}} \\
& \underset{\left( A \right)}{\mathop{\text{Intermediate}}}\,\to \underset{\left( B \right)}{\mathop{\text{Product}}}\, \\
\end{align}\]
TIPS/Formulae :
Iodoform test is given by compounds having $$ - COC{H_3}$$ group.
In acetone $$ - COC{H_3}$$ group is present. Further ethanol and isopropyl alcohol get oxidised to acetaldehyde and acetone respectively ( both having $$ - COC{H_3}$$ group ) in presence of $${I_2}$$ and they in turn give the test. Thus only diethyl ketone does not give this test.
173.
Which of the following statements is incorrect?
A
$$FeC{l_3}$$ is used in the detection of phenols.
B
Fehling solution is used in the detection of glucose.
C
Tollens' reagent is used in the detection of unsaturation.
D
$$NaHS{O_3}$$ is used in the detection of carbonyl compounds.
Answer :
Tollens' reagent is used in the detection of unsaturation.
The 40% solution of formaldehyde in water is sold in market under the name of formalin. Formaldehyde in the form of formalin ( 40% formaldehyde, 8% methanol and 52% water ) is used for preserving biological specimens.
Formaline solution also used as a disinfectants and commonly used in hardeness and nail varnish.
175.
Match the column I with column II and mark the appropriate choice.
This is an example of intramolecular Cannizzaro reaction.
178.
Study the following sequence of reactions and identify the product $$(Y).$$
\[C{{H}_{3}}CHO+HCHO\xrightarrow[\text{heat}]{\text{dil}\text{.}\,NaOH}\] \[X\xrightarrow[{{H}_{3}}{{O}^{+}}]{HCN}Y\]
A
\[C{{H}_{2}}=CH\underset{\begin{smallmatrix}
|\,\,\,\,\, \\
OH\,\,
\end{smallmatrix}}{\mathop{-CH-}}\,COOH\]
B
\[C{{H}_{3}}\underset{\begin{smallmatrix}
| \\
\,\,\,OH
\end{smallmatrix}}{\overset{\begin{smallmatrix}
\,\,\,CN \\
|
\end{smallmatrix}}{\mathop{-C-}}}\,COOH\]
C
\[C{{H}_{3}}C{{H}_{2}}\underset{\begin{smallmatrix}
|\,\,\,\,\,\, \\
OH\,\,\,
\end{smallmatrix}}{\mathop{-CH-}}\,COOH\]
D
\[C{{H}_{2}}=CH\underset{\begin{smallmatrix}
|\,\,\,\,\,\, \\
CN\,\,\,
\end{smallmatrix}}{\mathop{-CH-}}\,COOH\]